Sheet metal clamp



Dec. 25, 1956 w. M. 'roMPKlNs ET AL 2,775,155

SHEET METAL CLAMP Filed April l2. 1954 I as N INVENroRs WILL M. 75mm/Ms By 4lssro// l.. ELL/.s

Venice, Calif., assignors to Monogram Manufacturing Company, Culver City, Calif., a corporation of Cali fornia Application April 12, 1954, Serial No. 422,604

8 Claims. (Cl. 85-6) This invention relates generally to sheet metal clamps, and more particularly to an improved clamp of the general type disclosed in Patent No. 2,387,371, issued October 23, 1945, to Frank C. Wallace for clamps.

Such clamps employ the usual clamping or retaining pins which are reciprocably mounted in a body or housing and are adapted to be laterally opened by an intermediate spreader bar to engage against the back side of the Work. By drawing the pins inwardly towards the housing, the work, which typically comprises a pair of plates or sheets, is clamped tightly against the end of the body and is held in properly aligned position. To hold the pins inwardly use is made of a nut and screw which is able to exert a high pressure positively locking the pins in place so that the clamp is particularly adapted for use with relatively heavy and thick plates. In the disclosed clamp of the aforementioned patent, the locking nut takes the form of a Wing nut adapted to be rotated by hand to retract the retaining pins relative to the body. The disclosed construction also utilizes a stamped casing or body which reduces the cost of the clamp by eliminating screw machining operations.

ln the use of such clamps it has been found that it is often necessary to tighten the lock nut with a wrench in order to obtain sufficient clamping pressure. T o reduce the installation time it is desirable to make use of a power operated wrench or driver commonly known as nut runners. Such tools are capable of exerting reversible driving torque to rapidly advance or retract a screw and are commonly used in all types of factory assembly lines.

A wing nut and screw such as is used in the Wallace clamp is not adaptable for use with a power driven nut runner, and it is a major object of this invention to provide a clamp having a modified lock nut and screw which is particularly suited for use with a nut runner.

Another object of this invention is to provide an improved retaining member having a simplified and more easily assembled connection between the threaded plunger and the retaining pins.

It is also an object of the invention to provide an improved construction for the stamped casing or body permitting free rotation of the spreader bar as Well as the retaining pins.

A further object of the invention is to provide improved means for securing the casing and cover together so as to form a more rigid and durable body.

These and other objects and advantages of the invention will become apparent from the following detailed descrip- Y Patented Dec. `25, 1956 tangular body or casing 10 having extended through the end walls a reciprocable retaining member designated generally 11. Retaining member 11 is adapted to be extended through aligning holes 12 in a pair of plates or sheets S which it is desired to align and clamp tightly together. After insertion through holes 12, retaining member 11 is retracted relative to casing 10 and is caused to be laterally expanded so as to engage with -the rear surface of sheets S and draw the sheets tightly against the end of the casing.

As is best seen in Figure 3, casing 10 is formed as a stamped sheet metal member having side walls 14 and 15, a forward end Wall 16, and a bottom wall 17. Large ears 18 project upwardly from the rear portions of side walls 14 and 15 and the forward wall 16 is provided with a central circular opening 19. On the top edge of walls 14 and 15 near the front thereof are spaced opposed slots 20, and similar slots 21 are formed in the rear vertical edges of the walls at the bottom. The bottom wall 17 has opposed apertures 22 which are spaced slightly forward of slots 20 near the side corners. Above slots 21 the edges of walls 14 and 15 are angled inwardly for a short distance so as to define projecting lugs 23.

A cover plate 24 is adapted to fit on casing 10 and close the top and rear end walls thereof. Plate 24 is of elongated rectangular shape and has a downturned rear end wall 25 extended outwardly beyond side walls 14 and 15 and having spaced side slots 26 in a position to engage with lugs 23 while the wall portion therebelow drops into slots 21. Rear Wall 25 has a central circular opening 27 which lies in coaxial alignment with the opening 19 in the forward casing wall.

Extended along the top of plate 24 is a stitfening rib 28 and projecting upwardly from the side thereof are parallel ears 30. The spacing of ears 30 is such that they slide between casing ears 18 when the cover is installed in place. Lugs 31 extend outwardly near the front of plate 24 for engagement within slots 20, and the front of the plate is bent downwardly to form a forward end wall 32 tting between the casing side walls 14 and 15. The end wall 32 has an .enlarged downwardly open slot 33 therein defined by side legs 34, and the length of plate 24 is such that the wall 32 lies spaced rearwardly from the forward casing wall 16. Legs 34 are elongated and tit within bottom wall apertures 22 so as to hold the wall 32 against rearward bending. To lock plate 24 securely in place, a pin 36 is passed through ears 18 and 30.

Retaining member 11 has an elongated threaded plunger 40 at the rear end which is adapted to t slidably within casing 1G and extends outwardly through the rear plate opening 27. On the rear end of plunger 40 is an enlarged circular head 41 which is at and relatively thin. Head 41 acts as a rear stop for an operating nut 42 which is mounted on plunger 40 outwardly of casing 10 to fasten and release the clamp as will hereinafter be explained.

Projecting forwardly from plunger 4t) are a pair of retaining pins 43 which are of split semi-cylindrical shape having enlarged front noses 44 and enlarged rear flanges 45. Pins 43 extend through front casing opening 19 as well as the slot 33 formed in the rearwardly spaced plate end 32. In order to connect pins 43 to plunger 40, a connecting collar 46 is provided. "Collar 46 has a polygonal Vouter body fitting slidably and non-rotatably with'- in casing 1Q and is centrally bored with the rear portion 47 being threaded to engage the end of plunger 40. The front portion of colar 46 has a smooth bore 4S shouldered inwardly to a reduced opening 49. Bore 48 re.- ceives the flanged pin head 45 rotatably `therein with'the pins extending through reduced opening49. Heads :45

o cannot pass forwardly lthrough opening-49 andzare.. held .y Vrearwardlyby the endofiplunger 40. Thus pin's ,143' 'sare fixed against longitudinal movement relative to plunger and at the same time arefree for relative rotation.

The construction just described is such as to make the assembly of the vdevice very simple. Pins 43 are first pushed through collar 46' so that they project forwardly and this sub-assembly is then mounted within casing 10. After the cover plate 24 is dropped into place, the plunger 40 is inserted into casing 10 through the rear plate opening 27. Since collar 46 is held against rotation, the plunger 40 may be locked tightly within bore 47 lto complete the assembly of the retaining member. It can also be understood that the construction also facilitates the repair and replacement of parts during the life of the device.

Pins 43 are of spring material suited for lateral exure. Extended between pins 43 is a flat spreader bar 50 having a cross arm 51. Bar 50 projects forwardly through end opening 19 with cross arm 51 fitting within the space between the casing end wall 16 and the plate end wall 32. Bar 50 is free for rotation with pins 43, but is held against longitudinal movement by the cross arm 51. In order to prevent cross arm 51 from sliding through slot 33, a washer 52 is tted around pins 43 between plate wall 32 and the cross arm. The relative spacing of washer 52 and end walls 16 and 32 is such as to hold bar 50 tightly against longitudinal movement.

Bar 50 is of sufiicient length to pass through both of sheets S, but is considerably shorter than the retaining pins 43. When the latter are extended fully forward, they override the spreader bar 50 and lie together presenting the minimum diametral dimension. In this position, pins 43 are adapted to pass through the aligning holes 12 in the work S so that noses 44 are spaced rearwardly from back face of the rear sheet or plate. As pins 43 are retracted towards casing 10, they ride up on spreader 50 and are flexed laterally outwardly into the position shown in Figure 2. Noses 44 now extend outwardly beyond the wall of aligning holes 12 and cannot be retracted therethrough. The back faces of noses 44 are shouldered radially at 55 to provide a contact surface which solidly abuts against the rear sheet S and forces the sheets against the front wall 16 of the casing.

The previously mentioned operating nut 42 is provided to retract pins 43 rearwardly towards casing 10 in the manner just described. As nut 42 is rotated in an advancing direction, it is held from forward movement by the rear end wall 25 and the plunger 40 is pulled rearwardly retracting pins 43. To lock nut 42 when pins 43 are fully retracted it is preferable to provide a lock washer 56 between the nut and end wall 25. As

can be understood, nut 42 may be tightened so as to exert a very high clamping pressure on sheets S and hold them securely in alignment.

The design of nut 42, plunger 40 and head 41 is such as to permit the use of a nut runner for advancing the nut on the plunger. A typical socketed driving end 60 is illustrated in Figure 2 with the rear portion being shaft connected to the motor of a nut runner which is not shown. Nut 42, is, of course, of polygonal noncircular shape and the socket 60 engages non-rotatably therein with plunger 40 and head 44 extending into the socket. The diameter' of nut 42 across the flats is made at least large enough to circumscribe head 41 so 4that the latter is not rotated by socket 60 and there is no interference with the advancing rotation of the nut.

When `the use of the clamp has been completed, nut 42 is backed off from casing 10 with the socket 60. The enlarged head 41 prevents nut 42 from being removed from the plunger 40 where it could be easily l'ost. After nut 42 is spaced rearwardly from casing 10, the plunger 40 may be pushed forwardly to release pins 43 from engagement with the sheets S and the spreader bar 50. Becausel the clamp is adapted for operationby Vthe power driven nut runner, the time for installation and removal is greatly reduced. Also, a

very high torque may be placed on nut 42 to exert a strong clamping pressure.

While we have thus shown and described a preferred embodiment of the invention in some detail, it is to be understood that modifications of design and construction will be apparent to those skilled in the art. Therefore, we do not wish to be restricted to the foregoing except as deiined in the appended claims.

We claim:

1. A sheet metal clamp comprising: a casing having openings through the opposite ends thereof; a retaining member reciprocably mounted in said casing and projecting through said openings, said member having a threaded plunger at one end and a pair of laterally exible work engaging pins at the other end; a spreader bar rotatably mounted within the casing between the pins and held against longitudinal movement; coupling means on said plunger engaged within said casing to hold said plunger against rotation, said means being rotatably and releasably connected to said Work engaging pins to facilitate replacement of said pins and permit rotation thereof relative to said plunger; and a non-circular nut mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

2. A sheet metal clamp comprising: a casing having openings through the opposite ends thereof; a retaining member reciprocably mounted in said casing and projecting through said openings, said member including a threaded plunger at one end formed with a circular head, and a pair of separate laterally flexible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted in said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and a reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinally iixed relative to said plunger; and a noncirc'ular nut of a diameter across the flats to circumscribe said head mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

3. A sheet metal clamp comprising: a casing having openings through the opposite ends thereof; a retaining member reciprocably mounted in said casing and projecting through said openings, said member including a threaded plunger at one end formed with a circular head, and a pair of separate laterally exible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted in said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and a reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinally fixed relative to said plunger; a spreader bar rotatably mounted within said casing and held against longitudinal movement, said bar extending between said pins; and a non-circular nut of a diameter across 'the flats to circumscribe said head mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

4. A sheet metal clamp comprising: a casing having two sides, a bottom wall and an end wall with an opening therethrough; a plate mounted on and forming the top of the casing, said' plate having a right angled outer end fitting over and providing a 'closure for the open end of the casing and having an opening coaxial with the casing opening, the' other end of said vplate being bentk downwardly at 1ightanglesandl provided with a downwardly open slot, said last mentioned end being spaced from the end wall of said casing; means for preventing separation of said casing and said plate; a retaining member reciprocably mounted in said casing and projecting through the openings in said casing and said plate and said slot, said member having a threaded plunger at the outer end formed with a hat circular head and a pair of laterally exible and relatively rotatable work engaging pins at the other end; a spreader bar extending between said pins and having a cross arm rotatably mounted in said casing between the end wall of said casing and the slotted end of said plate; a washer mounted on said pins between said slotted plate end and said cross arm to hold said arm against longitudinal movement; and a non-circular nut of a diameter across the ats to circumscribe said head mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

5. A sheet metal clamp comprising: a casing having two sides, a bottom wall and an end wall with an opening therethrough; a plate mounted on and forming the top of the casing, said plate having a right angled outer end tting over and providing a closure for the open end of the casing and having an opening coaxial with the casing opening, the other end of said plate being bent downwardly at right angles and provided with a downwardly open slot, said last mentioned end being spaced from the end wall of said casing; means for preventing separation of said casing and said plate; a retaining member reciprocably mounted in said casing and projecting through the openings in said casing and said plate and said slot, said member including a threaded plunger passing through said plate opening and formed with a circular head, and a pair of separate laterally flexible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted in said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and la reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinally xed relative to said plunger; a spreader bar extending between said pins and having a cross arm rotatably mounted in said casing between the end wall of said casing and the slotted end of said plate; and nut means engaged on said plunger outwardly of said casing to advance and retract said plunger relative to said casing.

6. A sheet metal clamp comprising: a casing having two sides, a bottom wall and an end wall with an opening therethrough; a plate mounted on and forming the top of the casing, said plate having a right angled outer end fitting over and providing a closure for the open end of the casing and having an opening coaxial with the casing opening, the other end of said plate being bent downwardly at right angles and provided with a downwardly open slot, said last mentioned end being spaced from the end wall of said casing; means for preventing separation of said casing and said plate; a retaining member reciprocably mounted in said casing and projecting through the openings in said casing and said plate and said slot, said member including a threaded plunger passing through said plate opening and formed with a circular head, and a pair of separate laterally flexible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted in said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and a reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinally iixed relative to said plunger; a spreader bar extending between said? pins and .having a cross arm rotatably mounted in said casing between the end wall of said casing and the slotted end of said plate; a washer mounted on said pins between said slotted plate end and said cross. arm to hold said arm against longitudinal movement; and a non-circular nut of a diameter across the ats to circumscribe said head mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

7. A sheet metal clamp comprising: a casing having two sides, a bottom wall and an end wall with an opening therethrough, said bottom wall having a pair of spaced apertures therein near said end wall; a plate mounted on and forming the top of said casing, said plate having a right angled outer end fitting over and providing a closure for the open end ofv said casing and having an opening therethrough coaxial with said casing opening, the other end of said plate being bent downwardly and provided with a downwardly open slot dened by spaced legs which engage within said casing apertures; means for preventing separation of said casing and said plate; a retaining member reciprocably mounted in said casing and projecting through the openings in said casing and said plate and said slot, said member including a threaded plunger passing through said plate opening and formed with a circular head, and a pair of separate laterally flexible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted yin said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and a reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinally fixed relative to said plunger; a spreader bar extending between said pins and having a cross arm rotatably mounted in said casing between the end wall of said casing and the slotted end of said plate; a washer mounted on said pins between said slotted plate end and said cross arm to hold said arm against longitudinal movement; and a non-circular nut of a diameter across the flats to circumscribe said head mounted on said plunger outwardly of said casing and being advanceable against said casing and retractable outwardly against said head by a power driven nut runner to engage and release said retaining member.

8. A sheet metal clamp comprising: a casing having two sides, a bottom wall and an end wall with an opening therethrough, said bottom wall having a pair of spaced apertures therein near said end wall; a plate mounted on and forming the top of said casing, said plate having a right angled outer end fitting over and providing a closure for the open end of said casing and having an opening therethrough coaxial with said casing opening, the other end of said plate being bent downwardly and provided with a downwardly open slot defined by spaced legs which engage within said casing apertures; ears projecting upwardly trom the sides of said casing; ears projecting upwardly from said plate and adapted to lit between said casing ears; a pin extended through said ears to secure said plate to said casing; a retaining member reciprocably mounted in said casing and projecting through the openings in said casing and said plate and said slot, said member including a threaded plunger passing through said plate opening and formed with a circular head, and a pair of separate laterally flexible work engaging pins at the other end provided with enlarged inner and outer ends; a collar slidably and non-rotatably mounted in said casing and having one end portion formed with a chamber to receive the enlarged inner ends of said pins rotatably therein and a reduced bore for the outward passage of said pins, the other end portion of said collar being internally threaded to engage said plunger and hold said pins longitudinallyA fixed relative to said plunger; a spreader bar extending between said pins andv having a cross arm rotatably mounted' in said casing between the end wall of said casing and the slotted end of said plate; a washer mounted on said pins between said slotted plate end and said cross arm to hold said arm against longitudinal movement; a washer mounted on said plunger outwardly of said casing; and a non-circular nut of a diameter across the ats to circumscribe. said head mounted on said plunger outwardly of said last men- References Cited in the ile of thispatent UNITED STATES PATENTS 2,370,336 Wallace V Feb. 27, 1945 Wallace oct. 23, 1945 

